Large carnivores were scarce but very diverse in Europe more than one million years ago

Jesús Rodríguez and Ana Mateos, scientists at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH in Spanish), have just published an article in the Journal of Human Evolution which shows that the fauna of large carnivoran in Europe during the Early and Middle Pleistocene was extremely diverse, but the population densities of these species had to be very low, especially in comparison with the population densities of their current analogues in Africa.

The fauna of large carnivoran in Europe during the Early and Middle Pleistocene was extremely diverse, but the population densities of these species had to be very low, especially in comparison with the population densities of their current analogues in Africa [Credit: Jesus Rodriguez]

In this article entitled "Carrying capacity, carnivoran richness and hominin survival in Europe," they analyze and compare the biodiversity of carnivoran with the productivity of European ecosystems, between 500,000 and 1,600,000 years ago, and the Pleistocene ecosystems' carnivoran carrying capacity is estimated for the first time.

In order to complete this work, the authors have had to create their own paleoclimatic maps, and use these maps to estimate the number of herbivores (biomass) that the ecosystems of southern Europe could support during the Pleistocene, that is, their carrying capacity, and, from that data, determine the carnivoran density it could maintain on a stable basis.

"We have applied basic ecosystem functionality rules to discover what that world could have been like, hundreds of thousands or millions of years ago. Plant production, conditioned by climate, limits the number of herbivores in an ecosystem, and in turn the number of carnivoran that an ecosystem can maintain depends on the number of herbivores," Jesús Rodríguez explains.

Advantages for hominids

The work is a novel approach to the ecosystems of the Pleistocene, but its implications go further, and one of its most interesting consequences is that the first hominids that arrived in Europe, about one and a half million years ago, were faced with a situation very unlike those experienced by their ancestors in Africa.

This is because Europe offered much smaller variety and density of potential prey, but also carnivoran fauna, their potential competitors and predators, as diverse or even more so than Africa. "However, these predators were not as abundant as in the savannas from which they came, so the chances of having an unfavorable encounter with them were much lower," Ana Mateos points out.

These peculiar ecological conditions in European ecosystems could have provided significant advantages for the continent's earliest inhabitants, since the human niche would not completely overlap with other species'. "In fact, Homo is not, strictly speaking, exclusively a scavenger or hunter. Therefore, we consider that opportunism could have been the most successful survival strategy," Mateos concludes.